For your Mac and MacBook users who are already updated to the latest Sierra mac mac1313.4, you can already use eGPU as this support has been officially released to the public version of macOS.  Previously, this support is only available in Beta version to be tried and used by developers and people who are enthusiastic with the feature until this feature is ready to be released to the public.
Only, this feature can only be used on Mac computers that have been support Thunderbolt 3 connection yes That means, if there is still no Thunderbolt 3 connection like the MacBook Pro 2015, then this feature will not be enjoyed by you.
One or more eGPUs can be used on MacBook 2016 and later, iMac 2017 and iMac Pro. This feature is very important if you want to use technology that requires high graphics cards such as Virtual Reality, 3D Gaming, and so on.
It’s just that you may also be confused with any graphics card that can be used on Mac and MacBook already install MacOS High Sierra 10.13.4 update. Quiet, Apple has already released some external graphics card recommended for use on Mac and MacBook.
Apple recommends AMD Polaris, Vega 56, and Vega 64 combined with Thunderbolt chassis 3. For AMD Radeon RX 570 graphics card, RX 580 , and Radeon Pro WX 7100 you can use the following suggested chassis by Apple:
- OWC Mercury Helios FX3
- PowerColor Devil Box
- Sapphire Gear Box
- Sonnet eGFX Breakaway Box 350W
- Sonnet eGFX Breakaway Box 550W
- Sonnet eGFX Breakaway Box 650W
For you Windows users on Mac and MacBook with dual boot (Boot Camp), unfortunately this feature is not available at this time. You have to boot to macOS to use it.